Funds allow multiple entities to collectively invest in assets or investments that may otherwise be unavailable to individual entities. The value of a fund is generally the assets of the fund less the value of the liabilities of the fund. A master fund is an investment vehicle that enables individual investors to invest money into one or more underlying investments that are generally operated by professional managers. Master funds can generally be categorized by type, for example, discretionary funds, fund of funds, feeder funds, etc. A portfolio is a grouping of financial assets including, for example, stocks, bonds and cash equivalents, as well as their mutual, exchange-traded and closed-fund counterparts. Portfolios may be held directly by investors or managed by professionals.